1. Technical Field
The present invention relates to a ceramic substrate being subjected at its surface to an electroless plating, and a method of manufacturing the ceramic substrate.
2. Background Art
Heretofore, when a metallic film for joining a different metal or as a conductor is formed on the surface of the ceramic substrate, the following have been used as a process for direct electroless plating:
(a) a process in which the surface of the ceramic substrate is subjected to a surface roughening treatment with an etching solution containing an alkali metal compound, adsorbed with a catalyst for an electroless plating and then subjected to the electroless plating;
(b) a process in which an activated paste is applied to the surface of the ceramic substrate and baked to form a plated layer and then an electroless plating is applied to the plated layer;
(c) a process in which a resin sheet whose surface has been roughened is adhered to the surface of the ceramic substrate, and then a catalyst for an electroless plating is adsorbed on the resin sheet, which is subjected to the electroless plating; and
(d) a process in which an alumina paste containing an excessive amount of an organic binder than normal is print-applied onto a part or a whole surface of a green (ceramic) sheet and then simultaneously fired to form a ceramic substrate having a porous surface, and thereafter the surface of the ceramic substrate is subjected to an electroless plating (Japanese Patent laid open No. 59-161,896).